A condom is a physical barrier between a penis and another hole (like a mouth, an anus, or a front hole). They can be made out of latex, rubber or a synthetic material. They also come in different sizes (which is really important).
Because they’re a physical barrier, they serve to literally block the movement of fluids from one person to another (like semen into an anus, for example). That means that bacteria and viruses can’t get through – as long as the condom is used correctly.
Some common mistakes with condoms include using the wrong size (which can be painful if it’s too small, may not cover all of your penis if you have a long penis, or may fall off during sex if it’s too loose), damaging the condom when you take it out of the package, storing them incorrectly, or not putting them on correctly.
Practice makes perfect! Grab a couple from the local clinic (they usually give them out for free) and explore what works for you. Figure out how to put one on before you meet someone.
Because condoms protect against a range of STIs, they are considered one of the best general purpose protections against infection.